1. Field of the Invention
The present invention relates to an ultra violet rays generator (UV generator) by means of microwaves exitation comprising a step of irradiating a microwaves to an ultra violet rays lamp (UV lamp), such as an electrodeless lamp etc. in a microwave cavity, and more particularly, to a UV generator detachable of an ultra violet rays reflector (UV reflector) from focus ray type to parallel rays type etc., without changing the capacity of a microwave cavity (impedance), and thus, becoming changeable of rays, for example, from focus rays to parallel rays or contrary to this without changing microwave efficiency, and furthermore possible of obtaining UV of low temperature excluding infra red rays (IR), and thus, becoming possible of the irradiation in high efficiency to the substrates which hate high temperature heat, such as plastics, and moreover, to a UV generator in which a mechanism is simplified by omitting a wave guide.
2. Description of the Prior Art
There are conventionally known UV generators, such as a UV generator shown in FIG. 4, which is a prior application by the same applicant. (c.f. Japanese Utility Model application Ser. No. 1211264/1987)
The UV generator shown in FIG. 4 consists of a microwave generator 2 having a microwave antenna 1, a microwave guide 3 connected to the microwave generator 2 in such a manner that said microwave antenna 1 is projected thereinto, a microwave cavity 6 having an upper wall 5 in which a slot 4 is bored, connected to said microwave guide 3 in such a manner that said slot 4 is faced to said microwave antenna 1, an ultra violet rays (UV) reflector 8 having a window 7 for introducing microwave on the upper part thereof, detachably secured in said microwave cavity 6, and an ultra violet rays lamp 9 disposed under said window 7 and near the inside of said UV reflector 8, said UV reflector 8 being detachably secured by inserting the edges 10, 10 thereof into the bottom 11 of the microwave cavity. Furthermore, the UV reflector 8 is obtained by forming an interference film 13 on a light-transmitting base 12 shown in FIG. 3.
According to the afore-mentioned generator of the prior invention, the microwaves 14 of, for example, 2450 MHZ are, at first, generated from the microwave antenna 1 by the microwave generator 2. The generated microwaves 14 are efficiently introduced into the microwave cavity 6 through the wave guide 3 from the slot 4 of the upper wall 5, and in this microwave cavity 6, a UV lamp 9 is irradiated and exited with the microwaves 14 to generate UV 15. The obtained UV 15 are given to penetratively exclude infra red rays (IR) therefrom by the effect of the interference film 13 of the UV reflector 8, and to reflect only the residual UV in the main, and then, are supplied to irradiate the substrates which are not shown in the drawings through the mesh 16. The said UV are low temperature since it is given to exclude IR therefrom, which are originally included in the UV.
Furthermore, the UV reflector 8 is detachable without changing the capacity of the microwave cavity 6 since it is detachably secured in the microwave cavity 6, different from the wall of the microwave cavity 6, and thus, the microwave efficiency are not changed at all even though for example, a focus type UV reflector 8 is substituted by a parallel type, and then, it can be possible of changing only the directions or configurations of the UV.
The prior generator is detachable of only the UV reflector without changing the capacity of the microwave cavity, and thus becoming changeable of the directions or configurations of the UV without changing the microwave efficiency of the microwave cavity, and furthermore, it can obtain the UV of low temperature, exclusive of infrared rays (IR) originally included in said UV.
However, the mechanism of said prior generator is complicated because of the existence of said wave guide.